1. Field of the Invention
This invention relates to a TV observation system for endoscopes in which a battery type power supply and a light source are incorporated in an attachment TV camera.
2. Description of Related Art
In general, an endoscopic observation requires an illumination system, which includes a light source for supplying light to illuminate an object observed; a light guide for transmitting the light from the light source to the distal end of an endoscope; and an illumination lens placed at the distal end of the endoscope to irradiate the object with the light emerging from the light guide. The light source is constructed with a lamp for bringing about intense light, such as a xenon lamp or halogen lamp; a condenser lens for effectively concentrating the light emitted from the lamp on the entrance end face of the light guide; a wavelength-selective filter used for color temperature adjustment; and a stop mechanism for adjusting the amount of light. This light source, however, is equipped with a large-sized power supply section for turning on the lamp and a drive control section for the stop mechanism, and thus is great in volume and heavy in weight as the entire light source device.
In the endoscopic observation, the light source device is placed stationarily, together with a monitor, close to an observer. The endoscope body and the light source device are connected by a light guide cable to introduce the light from the light source device to the distal end of the endoscope. In order to uniformly illuminate the observation field of the endoscope, the distal end of the endoscope is provided with the illumination lens.
Endoscopes are available in fiberscopes and rigid endoscopes for making visual observations and videoscopes for displaying an observation image on a monitor. In recent years, the videoscope has been widely used because it allows many observers to make observations at a time, without undue fatigue. Although it is desirable that even when the fiberscope or rigid endoscope is used, observations are made through the monitor, it becomes necessary in this case to connect an attachment TV camera to the fiberscope or rigid endoscope.
FIG. 1 shows a conventional TV observation system for endoscopes which uses such an attachment TV camera. This system is designed so that an endoscope body 1 coupled through a light guide cable 2 with a light source device 3 is connected to an attachment TV camera 4 coupled through an electric signal cable 5 with a TV processor 6. A monitor 7 for displaying an observation image is connected to the TV processor 6.
The endoscope body 1 has an observing optical system and an illuminating optical system. The illuminating optical system includes a light guide fiber bundle extending from a joint section 8 provided in the endoscope body 1 to the distal end of the endoscope and an illumination lens provided on the exit side of the light guide fiber bundle. The observing optical system, on the other hand, is constructed with an objective lens, an image guide or relay lens for transmitting an image formed by the objective lens, and an eyepiece for observing the transmitted image. The light source device 3 is provided with a lamp and a condenser lens. The light guide cable 2 incorporates a light guide fiber bundle therein so that its entrance end is connected to the light source device 3, and light from the lamp which is concentrated by the condenser lens is received by the entrance end and is transmitted to its exit end connected to the joint section 8. The joint section 8 is provided with an imaging optical system composed of a lens and a conical fiber to connect the light guide of the light guide cable 2 with the light guide of the endoscope body 1. The light emerging from the light guide of the light guide cable 2 is rendered incident in a desired condensing state on the entrance end of the light guide of the endoscope body 1 by the imaging optical system.
The attachment TV camera 4 is removably mounted to the eyepiece section of the endoscope body 1, and incorporates a photographic lens and an image sensor therein so that the light emerging from the eyepiece of the endoscope body 1 is condensed by the photographic lens to form an object image on the image sensor, by which the object image is converted into an electric signal. The electric signal cable 5 extending from the attachment TV camera 4 is connected to the TV processor 6, which receives the signal from the image sensor and converts it into a signal by which the image can be displayed on the monitor 7.
The light source device 3, the TV processor 6, and the monitor 7 are usually mounted on a single large rack, and when they are moved, a considerably strong force is required to pull them near an observer. Of them, the light source device 3 is largest in size and heaviest in weight.
Thus, the conventional TV observation system for endoscopes mentioned above, although capable of bringing about intense light for illuminating the object, is not easy to move. Furthermore, because the endoscope body 1 is connected by the light guide cable 2 with the light source device 3, the light guide cable 2 constitutes an obstacle to observation, depending on the place where the observation is made. This restricts an observer's behavior and materially reduces his work efficiency.